Draft controller for locomotives



H. RICE. DRAFT CONTROLLER FOR LOCOMOTIVES. APPLICATION FILED. MAY 27, I92].

Patented Aug. 22, 1922.

lrIln l lll A {if q Hiya N N yd 4 li a ad rhea r. rant a l r theta HENRY M. RICE, OF KNOX VILLE, TENNESSEE.

DRAFT CON'TROLLER FOR LOCOll/IOTIVES.

llfltii fifidll. Specification of Letters Patent. Patented Aug 22, di til /Z,

Application filed May 27, 1921. Serial no. 473,001

T 0 all w 710m it may concern Be it known that T, HENRY M. 31012, a citizen of the United States, residing at Knoxville, in the county of Knox and State of Tennessee, have invented certain new and useful Improvements in Draft Controllers for Locomotives, of which the following is a specification.

This invention relates to means for controlling the draft and steam pressure in boilers and is intended moreparticularly for use upon locomotives, although it is adapted for use upon all steam boilers. The object of the invent-ion is to provide simple and eficient means whereby, when the steam pressure reaches a predetermined point, the p the draft box of the boiler will be broken and a counterdraft set up therethrough so that the temperature of the fire-box will be reduced and the steam pressure permitted to fall. The invention also seeks to provide a mechanism for the stated purpose which will be accessible at all times so that if repairs should he needed they may be readily made.

The invention is illustrated in the accompanying drawings and will be hereinafter fully set forth, and in the said drawings- Figure 1 is a view partly in side elevation and partly in section showing the improved apparatus mounted upon a portion of a locomotive;

Fig. 2 is an end elevation.

In carrying out my invention, 1 provide upon the front end of the locomotive boiler 1 in advance of the smoke stack 2, a box 3 provided with a swinging cover 4;. The said cover 4 is provided with a longitudinal slot 5 in one side of which a stud 6 may play and upon thesaid stud is pivotally engaged the end of the forwardly projecting arm 7 of an angle lever which is fulcrumed, as shown at 8, upon the side of the box 3. The depending arm 9 of the angle lever is curved so as to conform to the curvature of the boiler and in its lower end is provided with a longitudinal slot 10 which receives the stud or pin 11 on the front end of a piston rod 12. The said piston rod 12 plays through the front end of a cylinder 13 which is supported upon the boiler in any convenient manner and within the said cylinder a piston 14- is carried by the end of the piston rod, a coiled spring 15 being disposed within the cylinder between the said piston and the front end of the cylinder, as

partial vacuum in ,clearly shown in Fig. 1. The piston is, of

course, provided with the usual, packing rings whereby to effect a fluid-tight engage- ,ment with the wall of the cylinder and in .the upper portion of the cylinder in rear of the piston is an oil cup 16, while in the lower portion of the cylinder in rear of the piston is a drain cock 17. The rear end or head of the cylinder is equipped with a nipple 18 to which is coupled a steam pipe 19 leading from a governor valve casing 20 which is supported in any convenient manner upon the side of the boiler. Within the governor valve casing 20 is mounted a poppet valve 21 which is normally seated in the upper end of the inlet port 22 of said. casing and is held to its seat by a plunger 23 controlled by a spring 24:, the tension of which may be regulated by a screw plug or cap 25 threaded into the casing, as shown. The inlet port 22 is formed in the lower end of the governor valve casing and communicates directly with a steam pipe 26 which extends rearwardly therefrom to the steam space of the boiler into which it is tapped or otherwise fitted, as indicated at 27.

It will be readily noted that the draft box 3 is disposed to communicate with the upper portion of the draft or smoke chamber of the locomotive in advance of the boiler head and the dues of the same. The spring 24 is adjusted so that its tension will hold the valve 21 seated until the pressure of the steam reaches a predetermined point and when the steam pressure exceeds that point, the valve will be lifted and steam will then flow through the valve casing and the pipe 19 into and through the nipple 18 to enter the cylinder and bear upon the piston 14 therein. As soon as the pressure of the steam upon the piston 14 exceeds the tension of the spring 15, the piston will be pushed forward and the angle lever swung to the position shown in dotted lines in Fig. 1, whereupon the upper forwardly projecting arm 7 of the lever will raise the cover 4 to the position shown in dotted lines and air will at once flow through the draft box 3 into the draft or smoke chamber of the boiler and reduce the vacuum therein, setting up a counterdraft through the smoke stack so that the fire will not burn as intensely as before and the temperature of the firebox and of the lines will be lowered. The generation of steam will, consequently, be partly arrested and the pressure will fall,

When the pressure is reduced to a point below the strength of the spring 15, the piston 14 will be returned to its initial position and the cover 4 will be lowered ontolthe draft box 3 and close the same. The reduction of the, steam pressure will, of course, permit the governor valve 21 to engage its seat,

whereupon the draft through the fire-box will be again fully established and the fire will again become active and the generation of steam proceed as before.

From the foregoing description, taken in connection with the accompanying drawings, it will be readily noted that I have provided an exceedingly simple device whereby the steam pressure in the boiler will be' automatically prevented from reaching a dangerous degree and an economic consumption of fuel will be attained. All'the parts of'the mechanism are arranged exteriorly of the boiler so that the operation of the same maybe observed at all times and if repairs or renewals should become necessary they maybe readily made without requiring accessto the interior of the boiler at any point.

Minor repairs, furthermore, may be made without putting the boiler out of commission and the only change needed in boilers now in use is to form an opening over which the draft box 3 may be secured and to form a smaller opening to receive the end of the steam pipe 26. All joints, of course, will be packed to avoid leakage and the apparatus may be installed at a very low cost.

controlled means acting on said rod whereby to oscillate the lever.

In testimony whereof I affix my signature.

, HENRY M. RICE. [L. s.] 

